Apparatus for honing internal screw threads



J. H. HOERN April 29, 1941.

2 Sheets-Sheet -1 Filed Dec. 5, 1940 x mw wm 4N & w ma mm Q wm WW QW QM,

J. H. HOERN APPARATUS FOR HONING INTERNAL SCREW THREADS Filed Dec. 5, 1940 2 Sheets-Sheet 2 Qm N. Qh QM QM. V. w m kc? //A/// 7 4 2 7 ww Q S Q wwhw mm Y Z r & Q QM Q Patented Apr. 29, 1941 2,240,440 APPARATUS roa HONING INTERNAL scaaw reams Joseph H. Hoern, Birmingham, Mich, assignor to Eaton Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application December 5, 1940, Serial no. 368,572 12 Claims. -(o1. 51-1843) This invention relates to honing apparatus andhas for its primary object to provide a composite tool for honing internal screw threads.

Heretofore numerous ways and means have been suggested for honing an externally threaded part of an article, but insofar as this applicant knows, no practical commercial way has been demonstrated of providing a honed thread on internally threaded articles. In previous attempts at the solution of this problem wet lapping compounds have been tried'in conjunction with a suitable thread lap,-however, due to the inability to clean out all the compound from the base of the threads after the honing oper-' ation, the expedient hasnot been successful. Other attempts in the use of an internal thread grinder have been partially successful, but on account of the limited application of this procedure to internal thread diameters of suflicient magnitude to receive the thread grinder no practical solution has been oil'ered for honing threaded openings in the order of one inch diameter. or smaller sizes.

The present invention has successfully answered the need for an accurately finished and honed internal thread on a hardened article by use of a suitable compound adapter providing a support for a separate threaded insert comprised of diamond particles or similar wbrasive intered into a metallic binder of bronze powder, or other suitable binding material, and having the desired thread ground thereon. The threaded insert is secured within the hollow annular adapter for radial movement therein with a wedge shaped member interposed therebetween to accommodate for wear of the tool insert and to insure proper honing pressure with the threaded work piece; also to provide a positive, adjustable stop means.

Accordingly, the primary object of the present invention is the provision of an improved means for honing internally threaded work pieces; the

provision of means, as above described, having a tool insert with a threaded section secured within a threaded adapted supporting member and arranged for radial movement therein by means of a spring pressed wedge member associated therewith to insure uniform pressure of the abrasive insert throughout the length of the screw threads on individual work pieces to be honed.

A further object of this invention is the provision of apparatu for honing threads on internally threaded articles, having means to cause rotation of the honing tool several revolutions in one direction of rotation and then causing a i like number of revolutions in the opposite direction of rotation, the number of times the honing tool is rotated in any one direction being variaible selectively to suit the properties of the work to be operated upon.

Further and other objects and advantages of the present invention reside in the novel combination and arrangement of parts, and will be apparent from the following disclosures taken in conjunction with the drawings forming a part of this specification, and pointed out with particularity in the appended claims.

In the drawings like reference characters denote corresponding parts throughout the several views, and in which:

Fig. 1 is a side elevational view, with portions in section, of one form of apparatus used for rotating the honing tool; and

Fig. 2 is a vertical sectional view of Fig. 1; and

Fig. 3 is an enlarged longitudinal sectional view through the work receiving adapter and tool of the structure shown in Fig. 1; and

Fig. 4 is a side elevational view of the composite tool removed from Fig. 3; and

Fig. 5 is a top plan view thereof; and

Fig. 6 is a left-hand end elevational view of the composite tool as viewed in Fig. 4 illustrating the tapered foot thereof. V

Fig. 7 is a longitudinal sectional view similar to Fig. 3 but illustrating a modified form or work receiving adapter which mounts two honing tools.

Now having reference to the drawings, and

' particularly to Figs. 1-3, inclusive, there is shown a supporting table In upon the top of which is secured, by any suitable fastening means, a framework and housing, generally designated ii, for the honing apparatus about to be described. Upon a vertical extension of the framework housing It is a laterally extended hollow hub l2, having bushings II at either end thereof, and arranged to receive a hollow driven 1 spindle I! which projects from either end of the hub and has a toothed section I5a around the central portion thereof within the bore of the hub. The teeth Ilia are meshed with a gear wheel H, which forms a portion of a gear train, and through a smaller pinion gear l8 attached thereto, is driven by a toothed rack l9 operable in a slide 20 of the housing cover 2|, and extension Zia which covers the vertical movement of the rack and serves .as a dirt guard, as best shown in Fig. 2.

vertically reciprocable bya lock nut The rack may be reciprocated by any suitable means such as a motor driven crankshaft, not shown. It will now be apparent that by a proper selection of rack length and gear ratio the spindle l5 may be rotated any predetermined number of revolutions, at a selected velocity, in one direction and then reversed so as to rotate in the opposite direction, dependent upon the physical properties of the work operated upon and the extent of honing required.

The hollow spindle. l5, more particularly described, includes a plunger rod 23 which extends axially therethrough and is arranged to be normally uniformly spring loaded by means of a collar 24 pinned to the rod and against which coil spring 25 acts. A hollow tube 23, stationary and fixed to the housing, envelops the rod The composite honing tool insert, generally designated 43, forms an important part of this invention and is composed'of an abrading ma- 23 and has a threaded outer end for reception*- of a. shoulder screw 21, and a lock nut 23 by means of which the tension of the spring may be adjusted and fixed to vary the pressure exerted by the plunger rod 23. For releasing the plunger rod pressure a block 29 is rotatably fixed 30 thereto adjacent its outer end, and to which is attached an arm' 3| of the lever 32 pivoted about a pivot axis 33, which in turn is attached to table top H) by any suitable block fastening means 34. The lever 32 is extended through a slot in the table top and terminates adjacent the floor in a foot pedal, not shown,

under control of the operator for releasing the plunger rod pressure when introducing a new work piece or removing a finished one from the threaded adapter, rotatably fixed upon the opposite end of the spindle, and about to be described.

In the hollow countersunk end of the spindle I5, as best shown in Fig. 3, an annular hollow adapter 35 is retained therein for rotation with the spindle by means of pin 36 and set screw 31. The adapter 35 is readily removable and has a threaded section 38 with a thread lead selected to receive the screw threads of the particular work piece to be operated upon. A portion of the threaded periphery has been interrupted by a slotted opening into the hollow interior of the adapter and a honing tool, generally designated 40, inserted therein and retained by means of a spring pin 4|. The spring pin 4| may be made of music wire, or other suitable spring wire stock, and is inserted through the hollow countersunk opening 43 in the outer endoi' the adapter 35 and through enlarged openings 44, in opposite ends of the honing tool, which are connected by an intermediate bore the same diameter as the spring pin, and finally into a pilot opening 45 in the adapter. It will be evident that such mounting of the honing tool provides a resilient suspension so as to permit limited radial outward movement of the tool by means of the shoe backing 41 having a tapered foot 48 which bears against a cooperative wedge-shaped end on rod 49. The rod 49 has an opposite reduced end piloted in an opening in the plunger rod 23 and is arranged to be uniformly spring-loaded thereby, as previously described, and thereby to normally fix the tool in honing position, unless the lever-32 is actuated to retract the plunger and permit the tool to assume an inactive position, as when removing or receiving a work piece on the honing tool aboutto be described. When in spring loaded working position the wedge exerts equal pressure throughout its length uniformly in an outward direction on all portions of the hone.

tion are, as previously described, for

terial 50. such as diamond particles and/or similar abrasive dust with a bronze powder and 501- a metallic shoe-backing 41:

dered or bonded to The shoe portion 41 has the tapered foot 48 for cooperation with the wedge-shaped end of the rod 43, as previously described. The honing material may, if desir include any other form of abrading material such as aluminous oxide in a clay hinder or resinous materials, which are bonded in metallic, ceramic, or carborundum materials. In this instance, the finely powdered diamond dimt and particles are screened to the desired mesh and then sintered with a powdered metal, such as bonze or the like. Thereafter a thread section is accurately ground in the face of the abrading material which has the desired lead and pitch.

The advantage of making the hone this way, as distinguished from the use of wet lapping compounds, or powdered honing materials, is that the diamond abrasive particles are held in fixed position by the sintered alloy whereby they remain in the surface of the softer metals which act as a support for the diamond particles. If an ordinary lap were used with powdered abrasive, as has been known heretofore, the abrasive would be very dimcult to remove from the bottom of the honed screw threads, and, also, such hones will not make a straight hole, as it is almost impossible to avoid honing the threads this way larger at the beginning of the screw threads than near the opposite end thereof. With the present honing tool the wedge will move all portions of the honing surface outward with equal and uniform pressure to form internal screw threads of uniform diameter throughout their length. Furthermore, disclosed with an accurate thread formed therein, upon becoming worn, can be reground and the wedged-end rod be operated to force the tool in honing engagement with the work, thus making it possible to economically use the insert throughout a, large number of regrindings.

In Fig. 7 the honing tool insert idea has been carried a bit farther, and, in place of a single tool, a pair of diametrically opposed inserts are shown. It will be apparent that more than one honing toolin a single adapter is desirable when the screw threaded opening to be honed is classified as being in a nominally large size, because in those instances the area required to be covered by a single insert tool is too extensive and the tool life too short, thus the need for two or more hones to reduce the wear on the individual tool. In the present instance only the adapter, generally designated 35a' has been increased in diameter to accommodate a pair of insert tools 43 as previously described. Obviously, since the tapered surfaces 48 of the shoes 41 present opposed tapered surfaces, the wedged-end of the rod 43a will cause equal movement of each tool in diametrically opposite directions. The remaining parts, construction, and mode of opera the single insert tool of Fig. 3. If desired for honing use upon still larger internal screw threaded diam eters the number of separate tool inserts may be increased to four in number by simply having two pairs of diametrically opposed tools at opposite ends of a pair of diameters of the adapter at right angles to each other, thus the inserts would be spaced at 0. honing tool insert as around the periphery of the adapter instead of 180 as shown in the present instance.

In the use of the honing tools above described it maybe desirable to provide a more positive stop means and adjustment for controlling the extent of the honing operation than the spring, shoulder screw and lock nut 21, and 28, previously identified. Accordingly, as shown in Figs. 1 and 2, the lever arm 3i may have an axial extension 3m above the spring pressed plunger rod 23, with which it is associated and fixed thereto. A boss 2 lb which may be formed as ,a part of the housing it has athreaded opening therethrough for reception of a suitably threaded rod 3), which is arranged to contact the lever arm extension 3la at one end, and upon the opposite end of which is a thumb screw handle adjustment Sic in close proximity to the working position of the machine operator. In the use of this stop means it will be apparent the operator can readily gauge a finished work piece and make any necessary adjustment by means of the thumb screw 3lc to increase or decrease themaximum outward movement of the honing pressure a predetermined amount, regardless of the time element that the work piece is allowed to remain over the tool. Thus a positive means for uniformity of honing operations on successive work pieces is provided rather than being dependent upon the skill and watchfulness of the individual operator.

From.the foregoing disclosures it will be apparent a novel honing tool insert and apparatus have been described for operating upon internal screw threads, which accomplishes, among other things, the objects and advantages of the invention first enumerated. However, it is not intended to be limited to the specific embodiments described, which are merely for purposes of illustration, as many formal modifications will present themselves to those skilled in the art to which this invention relates, without departing from the spirit and substance of the invention as defined by the following claims.

What I claim is:

1. In apparatus of the character described, a composite tool for honing female threads on articles, said tool comprising in combination; a hollow adapter member having a peripheral threaded section selected for reception of the threaded article to be honed, said adapter member having its threaded periphery interrupted by a slotted opening formed therein, and a threaded section formed of a honing material arranged to be moved in said opening into or out of presentation with the threads of the article to be honed.

2. In apparatus of the'character described, a composite tool for honing female threads on articles, said tool comprising in combination; a hollow adapter member having a peripheral threaded section selected for reception of the threaded article to be honed, said adapter member having a slotted opening formed therein, a threaded section formed of a honing material arranged to be moved in said opening into or out of presentation with the threads of the article to be honed,

said honing section comprising an abrasive fixed to a shoe backing with an inclined foot portion 3. In apparatus of the character described, a composite tool for honing female threads on articles, said tool comprising in combination; a hollow adapter membe having a peripheral threaded section selecte for reception of the threaded article to be honed, said adapter member having a slotted opening formed therein, a threaded section formed of a honing material arranged to be radially moved in said opening into or out of presentation with the threads of the article to be honed, said honing section comprising an abrasive material and a metallic binder suitably bonded to a shoe backing having a tapered foot, and a reciprocable wedge member within said hollow adapter beneath the tapered foot of said shoe adapted to be moved thereagainst to effect movement of the hone into or out of working position. I

4. In apparatus for honing internal threads arranged to be rotated periodically in clockwise and counterclockwise directions of rotation, the combination with a hollow threaded adapter member selected to threadedlyreceive internal screw threads of a work piece to be honed, of a composite honing tool; said honing tool comprising an abrasive material fixed in a molded metallic powder and bonded to a metal backing shoe, said abrasive material having'a thread section ground therein with a lead corresponding to the threads of its adapter, said shoe having a tapered foot arranged to be received in said hollow adapter member with the threaded abrading material projecting radially therefrom to match the threads of the adapter, and the tapered foot of said shoe arranged to be acted upon with a constant pressure by a complementary tapered part of said apparatus to insure uniform honing pressures with successive work pieces.

5. In apparatus for honing internal threads of a work piece, the combination with a hollow partially threaded and slotted adapter member selected to 'threadedly receive the internal screw threads of a work piece to be honed, of a composite honing tool insert, said apparatus arranged to rotate the work piece periodically in clockwise and counterclockwise directions of rotation, said honing tool comprising an abrasive material fixed in a molded bronze powder and bonded to a metal backing shoe having a tapered foot, said abrasive material having a thread section ground therein with a thread lead corresponding to the threads of the adapter, said shoe arranged to be received in the slot of said hollow adapter member with the threaded abrasive projecting radially therefrom to complete the matched threads of the adapter, and springpressed means in said apparatus arranged to act on the tapered foot of said shoe with uniform pressure to provide non-variable honing pressures of the abrading tool with successive work pieces.

6. In apparatus of the character described, a composite tool for honing internal screw threads, said tool comprising in combination, a hollow adapter member having a. peripheral threaded section selected for reception of the internal screw threads to be honed, said adapter having its threaded periphery interrupted and a slotted opening formed therein, and an abrasive tool inserted in said slotted opening having an outer thread section ground therein with a thread lead matched with and completing said interrupted threaded periphery of the adapter including means for moving all the working surface of said tool insert equally into honing engagement throughout the length of the screw threads of a work piece.

'I. In apparatus of the character described, a composite tool for honing internal threads on'articles; said tool comprising in combination, a hollow adapter member having a peripheral threadin said opening into or out of presentation with the threads of the article to be honed, said honing sections comprised of abrasive materials fixed in a 'metallic backing and bonded to shoes having tapered surfaces, and wedge means in said. holhow adapter arranged to be forced between the tapered surfaces of said honing shoes to produce said radial movement.

8. Apparatus for honing internal screw threads of a work piece comprising in combination, a hollow spindle powered by means arranged to move through several clockwise and counterclockwise rotations periodically, a hollow adapter arranged to be removably secured to one end'of said powered spindle and having an external threaded portion of selected size and lead providing a threaded support for reception of the internal threads of the work to be honed, said adapter having a slotted opening interrupting a portion of its threaded periphery and a radially movable honing tool with a matched peripheral thread section accurately ground thereon inserted in said slotted portion, an actuator rod extending through said hollow spindle and adapter arranged to radially move all the working portions of said tool uniformly into honing engagement with the work, and means including a lever arm associated with said actuator rod for manually moving the same at will.

9. Apparatus for honing the internal screw threads of a work piece comprising in combination, a hollow spindle powered by means arranged to cause periodical rotationin forward and backward directions, a hollow adapter rotatably secured to one end of said spindle and having an external threaded portion of selected size and lead, according to the threads of the work piece, to provide a threaded support therefor, said adapter having its threaded portion interrupted by a slotted opening cut therein, a tool with a working face of honing material having an accurately ground threaded section thereon with a lead corresponding to that of the work piece arranged to be moved radially in said slotted opening to complete said interrupted thread ,periphcry, and means for projecting all the working portion of said tool uniformly into honing engagement with the threads of the work piece.

10. Apparatus for honing the internal screw. threads of a work piece comprising in combination, a hollow spindle powered by means arranged to cause periodical rotation in forward and backward directions, a hollow adapter rotatably secured to one end of said spindle and having an external threaded portion of selected size and lead accordingto the threads of the work piece to provide a threaded support therefor, said adapter having its threaded portion interrupted by a slotted opening cut therein, a tool with a working face of honing material having an accurately ground threaded section therein with a lead corresponding to that of the work piece arranged to be moved radially in said slotted opening to complete said interrupted-thread periphery, means for moving said tool into honing engagement with the threads of the work piece, and

spring pressed means for-normally maintaining all the working surface of ,said honing tool in said powered spindle and having an external threaded portion of selectedsize and lead providing a threaded support for reception of the internal threads of the work to be honed, said adapter having a slotted opening interrupting a portion of its threaded periphery and a radially movable honing tool with'a matched peripheral thread section accurately ground thereon inserted in said slotted portion, an actuator rod extending through said hollow spindle and adapter arranged to radially move all the working portions of said tool uniformly into honing engagement with the work, means including a lever arm associated with said actuator rod for manually moving the same at will, and means associated with said leverarm providing a positive stop means for limiting the maximum honing engagement of the tool with the work piece.

12. Apparatus for honing the internal screw threads of a work piece comprising in combination, a hollow spindle powered by means arranged to cause periodical rotation in forward and backward directions, a hollow adapter rotatably secured to one end of said spindle and having an external threaded portion of selected size and lead according to the threads of-the work piece to provide a threadedsupport therefor, said adapter having its threaded portion interrupted by a. slotted opening cut therein, a tool with a working face of honing material having an accurately ground threaded section therein with a lead corresponding to that of the work piece arranged to be moved radially in said slotted opening to complete said interrupted thread periphery, means for moving said toolinto honing engagement with the threads of the work piece, spring pressed means for normally maintaining all the working surface of said honingtool in equal and uniform honing engagement throughout the screw threads of the piece to be honed, and stop means comprising a manually adjustable member under control of the operator and associated with said tool moving means for limiting maximum effective honing engagement of the tool with the work piece.

. JOSEPH H. HOERN.

CERTIFICATE OF CORRECTION. Patent No. 2,2L o,lmo'. April 29, 19L;1.

JOSEPH H. HOERN.

It is hereby. certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page-l, first columnrline 50, for "intered" read -sintered--; and that the said Letters Patent shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this Zhth day of June, A. 13., 191 1.

Henry van Arsdale, (Seal) Acting Commissioner of Patents. 

